Skin care compositions containing geranyl geraniol and retinol or retinyl esters

ABSTRACT

Geranyl geraniol inhibits esterification of retinol into inactive retinyl esters. Thus, effects of the retinol or retinyl esters in combination with geranyl geraniol are analogous to treatment with retinoic acid.

FIELD OF THE INVENTION

The present invention relates to skin care compositions containinggeranyl geraniol and retinol or retinyl esters.

BACKGROUND OF THE INVENTION

Retinol (vitamin A) is an endogenous compound which occurs naturally inthe human body and is essential for normal epithelial celldifferentiation. Natural and synthetic vitamin A derivatives have beenused extensively in the treatment of a variety of skin disorders andhave been used as skin repair or renewal agents. Retinoic acid has beenemployed to treat a variety of skin conditions, e.g., acne, wrinkles,psoriasis, age spots and discoloration. See e.g., Vahlquist, A. et al.,J. Invest. Dermatol., Vol. 94, Holland D. B. and Cunliffe, W. J. (1990),pp. 496-498; Ellis, C. N. et al., "Pharmacology of Retinols in Skin",Vasel, Karger, Vol. 3, (1989), pp. 249-252; Lowe, N. J. et al.,"Pharmacology of Retinols in Skin", Vol. 3, (1989), pp. 240-248; PCTPatent Application No. WO 93/19743.

It is believed that the use of retinol or esters of retinol would bepreferred over retinoic acid. Retinol is an endogenous compound whichoccurs naturally in the human body and is essential for normalepithelial cell differentiation. Retinol is also considered much saferthan retinoic acid. Esters of retinol hydrolyze in-vivo to produceretinol. It is believed that retinyl esters and retinol aremetabolically converted in the skin into retinoic acid according to thefollowing mechanism: ##STR1## However, most of the endogenously appliedretinol is rapidly converted into inactive retinyl esters for storage inepidermal cells (keratinocytes). Esterification of retinol into inactiveretinyl esters is achieved in cells by transfer of a fatty acyl groupfrom an acyl CoA, catalyzed by the enzyme acyl CoA retinol transferase(ARAT), or by the transfer of an acyl group from phosphatidyl choline,catalyzed by the enzyme lecithin retinol acyl transferase (LRAT). Theseesterification reactions are very efficient in keratinocytes--themajority (95%) of cellular retinoids are in the form of retinyl fattyesters. Thus, unfortunately, although retinol and retinyl esters aresafer to use than retinoic acid, they are less effective than retinoicacid at providing skin benefits.

The present invention is based, in part, on the discovery that geranylgeraniol inhibits these esterification reactions and thus potentiatesthe action of retinyl ester on retinol by increasing the amount ofretinol available for conversion to retinoic acid. Thus, a mixture ofgeranyl geraniol with retinol or retinyl esters mimics retinoic acid yetis safer to use than retinoic acid.

Geranyl geraniol is a noncyclic polyunsaturated diterpene alcohol.Slavtcheff et al., U.S. Pat. No. 5,484,597, disclose cosmeticcompositions containing C₁₀ -C₆₀ terpenes. However, it has beendiscovered as part of the present invention, that geranyl geraniol issubstantially more potent at inhibiting retinol esterification thanother terpenes, e.g., farnesol.

SUMMARY OF THE INVENTION

The present invention includes, in part, a skin conditioning compositioncontaining:

(a) from about 0.001% to about 10% of retinol or a retinyl ester;

(b) from about 0.0001% to about 50% of geranyl geraniol; and

(c) a cosmetically acceptable vehicle.

The term "conditioning" as used herein means prevention and treatment ofdry skin, photodamaged skin, appearance of wrinkles, age spots, agedskin, increasing stratum corneum flexibility, lightening skin color,controlling sebum excretion and generally increasing the quality ofskin. The composition may be used to improve skin desquamation andepidermal differentiation.

The presence of geranyl geraniol in the inventive product substantiallyimproves the performance of retinal or a retinyl ester.

According to the present invention, by virtue of including an effectiveamount of geranyl geraniol into compositions containing retinol or aretinyl ester, the performance of the compositions is substantiallyimproved. Alternatively, lower levels of retinol or a retinyl ester maybe included in the composition containing geranyl geraniol to equal theperformance of a similar formulation without geranyl geraniol.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The inventive compositions contain, as a first essential ingredient, acompound selected from the group consisting of retinol or a retinylester. The term "retinol" includes the following isomers of retinol:all-trans-retinol, 13-cis-retinol, 11-cis-retinol, 9-cis-retinol,3,4-didehydro-retinol. Preferred isomers are all-trans-retinol,13-cis-retinol, 3,4-didehydro-retinol, 9-cis-retinol. Most preferred isall-trans-retinol, due to its wide commercial availability.

Retinyl ester is an ester of retinol. The term "retinol" has beendefined above. Retinyl esters suitable for use in the present inventionare C₁ -C ₃₀ esters of retinol, preferably C₂ -C₂₀ esters, and mostpreferably C₂, C₃, and C₁₆ esters because they are more commonlyavailable. Examples of retinyl esters include but are not limited to:retinyl palmitate, retinyl formate, retinyl acetate, retinyl propionate,retinyl butyrate, retinyl valerate, retinyl isovalerate, retinylhexanoate, retinyl heptanoate, retinyl octanoate, retinyl nonanoate,retinyl decanoate, retinyl undecandate, retinyl laurate, retinyltridecanoate, retinyl myristate, retinyl pentadecanoate, retinylheptadeconoate, retinyl stearate, retinyl isostearate, retinylnonadecanoate, retinyl arachidonate, retinyl behenate, retinyllinoleate, retinyl oleate.

The preferred ester for use in the present invention is selected fromretinyl palmitate, retinyl acetate and retinyl propionate, because theseare the most commercially available and therefore the cheapest. Retinyllinoleate is also preferred due to its efficacy.

Retinol or retinyl ester is employed in the inventive composition in anamount of from about 0.001% to about 10%, preferably in an amount offrom about 0.01% to about 1%, most preferably in an amount of from about0.01% to about 0.5%.

The second essential ingredient of the inventive compositions is geranylgeraniol, which has the following structure: ##STR2##

Geranyl geraniol is included in the inventive compositions in an amountranging from about 0.0001% to about 50%, preferably from about 0.01% toabout 10%, most preferably from about 0.1% to about 5%.

Cosmetically Acceptable Vehicle

The composition according to the invention also comprises a cosmeticallyacceptable vehicle to act as a dilutant, dispersant or carrier for theactive components in the composition, so as to facilitate theirdistribution when the composition is applied to the skin.

Vehicles other than water can include liquid or solid emollients,solvents, humectants, thickeners and powders. An especially preferrednonaqueous carrier is a polydimethyl siloxane and/or a polydimethylphenyl siloxane. Silicones of this invention may be those withviscosities ranging anywhere from about 10 to 10,000,000 centistokes at25° C. Especially desirable are mixtures of low and high viscositysilicones. These silicones are available from the General ElectricCompany under trademarks Vicasil, SE and SF and from the Dow CorningCompany under the 200 and 550 Series. Amounts of silicone which can beutilized in the compositions of this invention range anywhere from 5 to95%, preferably from 25 to 90% by weight of the composition.

The cosmetically acceptable vehicle will usually form from about 5 toabout 99.9%, preferably from about 25 to about 80% by weight of thecomposition, and can, in the absence of other cosmetic adjuncts, formthe balance of the composition.

Optional Skin Benefit Materials and Cosmetic Adjuncts

An oil or oily material may be present, together with an emulsifier toprovide either a water-in-oil emulsion or an oil-in-water emulsion,depending largely on the average hydrophilic-lipophilic balance (HLB) ofthe emulsifier employed.

Various types of active ingredients may be present in cosmeticcompositions of the present invention. Various types of activeingredients may be present in cosmetic compositions of the presentinvention. Actives are defined as skin or hair benefit agents other thanemollients and other than ingredients that merely improve the physicalcharacteristics of the composition. Although not limited to thiscategory, general examples include sunscreens, tanning agents.

Sunscreens include those materials commonly employed to blockultraviolet light. Illustrative compounds are the derivatives of PABA,cinnamate and salicylate. For example, octyl methoxycinnamate and2-hydroxy-4-methoxy benzophenone (also known as oxybenzone) can be used.Octyl methoxycinnamate and 2-hydroxy-4-methoxy benzophenone arecommercially available under the trademarks, Parsol MCX andBenzophenone-3, respectively.

The exact amount of sunscreen employed in the emulsions can varydepending upon the degree of protection desired from the sun's UVradiation.

Another preferred optional ingredient is selected from essential fattyacids (EFAs), i.e., those fatty acids which are essential for the plasmamembrane formation of all cells, in keratinocytes EFA deficiency makescells hyperproliferative. Supplementation of EFA corrects this. EFAsalso enhance lipid biosynthesis of epidermis and provide lipids for thebarrier formation of the epidermis. The essential fatty acids arepreferably chosen from linoleic acid, γ-linolenic acid, homo-γ-linolenicacid, columbinic acid, eicosa-(n-6,9,13)-trienoic acid, arachidonicacid, γ-linolenic acid, timnodonic acid, hexaenoic acid and mixturesthereof.

Emollients are often incorporated into cosmetic compositions of thepresent invention. Levels of such emollients may range from about 0.5%to about 50%, preferably between about 5% and 30% by weight of the totalcomposition. Emollients may be classified under such general chemicalcategories as esters, fatty acids and alcohols, polyols andhydrocarbons.

Esters may be mono- or di-esters. Acceptable examples of fatty di-estersinclude dibutyl adipate, diethyl sebacate, diisopropyl dimerate, anddioctyl succinate. Acceptable branched chain fatty esters include2-ethyl-hexyl myristate, isopropyl stearate and isostearyl palmitate.Acceptable tribasic acid esters include triisopropyl trilinoleate andtrilauryl citrate. Acceptable straight chain fatty esters include laurylpalmitate, myristyl lactate, oleyl eurcate and stearyl oleate. Preferredesters include coco-caprylate/caprate (a blend of coco-caprylate andcoco-caprate), propylene glycol myristyl ether acetate, diisopropyladipate and cetyl octanoate.

Suitable fatty alcohols and acids include those compounds having from 10to 20 carbon atoms. Especially preferred are such compounds such ascetyl, myristyl, palmitic and stearyl alcohols and acids.

Among the polyols which may serve as emollients are linear and branchedchain alkyl polyhydroxyl compounds. For example, propylene glycol,sorbitol and glycerin are preferred. Also useful may be polymericpolyols such as polypropylene glycol and polyethylene glycol. Butyleneand propylene glycol are also especially preferred as penetrationenhancers.

Exemplary hydrocarbons which may serve as emollients are those havinghydrocarbon chains anywhere from 12 to 30 carbon atoms. Specificexamples include mineral oil, petroleum jelly, squalene andisoparaffins.

Another category of functional ingredients within the cosmeticcompositions of the present invention are thickeners. A thickener willusually be present in amounts anywhere from 0.1 to 20% by weight,preferably from about 0.5% to 10% by weight of the composition.Exemplary thickeners are cross-linked polyacrylate materials availableunder the trademark Carbopol from the B. F. Goodrich Company. Gums maybe employed such as xanthan, carrageenan, gelatin, karaya, pectin andlocust beans gum. Under certain circumstances the thickening functionmay be accomplished by a material also serving as a silicone oremollient. For instance, silicone gums in excess of 10 centistokes andesters such as glycerol stearate have dual functionality.

Powders may be incorporated into the cosmetic composition of theinvention. These powders include chalk, talc, Fullers earth, kaolin,starch, smectite clays, chemically modified magnesium aluminum silicate,organically modified montmorillonite clay, hydrated aluminum silicate,fumed silica, aluminum starch octenyl succinate and mixtures thereof.

Other adjunct minor components may also be incorporated into thecosmetic compositions. These ingredients may include coloring agents,opacifiers and perfumes. Amounts of these materials may range anywherefrom 0.001 % up to 20% by weight of the composition.

Use of the Composition

The composition according to the invention is intended primarily as aproduct for topical application to human skin, especially as an agentfor conditioning and smoothening the skin, and preventing or reducingthe appearance of wrinkled or aged skin.

In use, a small quantity of the composition, for example from 1 to 5 ml,is applied to exposed areas of the skin, from a suitable container orapplicator and, if necessary, it is then spread over and/or rubbed intothe skin using the hand or fingers or a suitable device.

Product Form and Packaging

The topical skin treatment composition of the invention can beformulated as a lotion, a fluid cream, a cream or a gel. The compositioncan be packaged in a suitable container to suit its viscosity andintended use by the consumer. For example, a lotion or fluid cream canbe packaged in a bottle or a roll-ball applicator, or a capsule, or apropellant-driven aerosol device or a container fitted with a pumpsuitable for finger operation. When the composition is a cream, it cansimply be stored in a non-deformable bottle or squeeze container, suchas a tube or a lidded jar.

The invention accordingly also provides a closed container containing acosmetically acceptable composition as herein defined,

The following specific examples further illustrate the invention, butthe invention is not limited thereto.

MATERIALS AND METHODS Cell Culture

Human keratinocytes, isolated from neonatal foreskin by trypsintreatment were grown in Dulbecco Modification Eagle (DME) Hams F12 (1:1)medium/10% fetal calf serum in the presence of irradiated 3T3 mousefibroblasts for establishing dividing keratinocyte colonies. Cells weregrown under the above condition until their second passage and keptfrozen for future use. Frozen second passage keratinocytes were thawedand plated into the above medium and grown for five days before theywere switched to a serum-free MCDB 153-based medium keratinocyte growthmedium (KGM) from Clonetics Corporation, San Diego, Calif., containing0.15 mM Ca, or keratinocyte serum-free media (KSFM) from GIBCOcontaining 0.09 mM Ca). On day 7, when the cells were 80-90% confluent,they were trypsinized and plated in the serum-free medium for thevarious experiments.

Thymidine Assay ³ H-Thymidine Incorporation and KeratinocyteProliferation

The incorporation of ³ H-thymidine by cultured keratinocytes was used asan assay of keratinocyte proliferation. Thymidine is one of fourdeoxynucleosides which are the monomeric units of DNA, the universallibrary of genetic information in the animal kingdom. Prior to celldivision of a somatic cell such as a keratinocyte, the complete genomeof the cell undergoing cell division is replicated. This involves largescale DNA synthesis by the cell and enables both daughter cells toreceive identical copies of the genetic material. When 3H-thymidine isincluded in the culture media of keratinocytes which are synthesizingDNA in preparation for cell division then the labelled nucleoside isincorporated into the newly synthesized DNA. The extent of incorporationof ³ H-thymidine into a population of cells is proportional to the rateof DNA synthesis by this population of cells and therefore an indicationof their cellular proliferation.

For Example 1, the following procedure was employed to measure thymidineincorporation:

Keratinocytes (that were cultured as described above) were plated in 24well plates at a density of about 20,000 cells per well in 1 ml media.After incubation for four days or until the cells were 60-70% confluent,the media was changed. Test compounds were added (in triplicate) to thewells 24 hours after the media change, and four hours later 1 μl ³H-Thymidine in 50 μl media was added per well. Cells were incubated fora further 24 hours. Media was removed from the cells, 10% ice coldtrichloroacetic acid (TCA) added and plates were incubated on ice for 30minutes. Cells were washed five times with 5% TCA and allowed todissolve in 500 μl 0.1M NaOH for at least one hour (usually overnight).The preparations were neutralized with 0.1M HCl; 50 μl of the cellpreparation was used to determine total protein content. Disintegrationsper minute (DPM) from ³ H labelling of DNA was determined by liquidscintillation counting of 900 μl of the cell preparation. Thymidineincorporation results were expressed as DPM/μg protein.

For Example 3, the following procedure was employed to measure thymidineincorporation:

Human keratinocytes were plated in 24-well plates at a density of 40,000cells/well in 1 ml keratinocyte growth media. The cells were allowed togrow until they were 60-70% confluent (approx. 4 days), after which theywere treated (in triplicate) with test agents in media for 4 hours.Tritiated thymidine (1 microcurie/ml) was then added, and the cells wereincubated for an additional 18 hrs. The medium was removed and the cellswere incubated for 30 minutes with ice cold 10% trichloroccetic acid.The cells were then washed 5× with 5% TCA and dissolved in 0.5 ml 0.1MNaOH. After neutralization with 0.1M HCl, aliquots were removed tomeasure protein and radioactivity by liquid scintillation counting.

Transglutaminase Assay Transglutaminase Assay and KeratinocyteDifferentiation

During the process of terminal differentiation in the epidermis, a 15 nmthick layer of protein, known as the cornified envelope (CE) is formedon the inner surface of the cell periphery. The CE is composed ofnumerous distinct proteins which have been cross-linked together by theformation of N^(E) -(γ-glutamyl) lysine isodipeptide bonds catalyzed bythe action of at least two different transglutaminases (TGases)expressed in the epidermis. TGase I is expressed in abundance in thedifferentiated layers of the epidermis, especially the granular layer,but is absent in the undifferentiated basal epidermis. Thus TGase I is auseful marker of epidermal keratinocyte differentiation with high TGaseI levels indicating a more differentiated state. An ELISA based TGase Iassay, using a TGase I antibody, was used to assess the state ofdifferentiation of the cultured keratinocytes in the examples thatfollow.

Keratinocytes (cultured as described above) were plated in 96 wellplates at a density of 3,000 cells per well in 200 μl media. Afterincubation for four days the media was changed to media containing testcompounds (six replicates per test). The cells were cultured for afurther 72 hours after which time the media was aspirated and the platesstored at -70° C. Plates were removed from the freezer, and the cellswashed with PBS. 100 μl sterile water was added and the cells werefreeze fractured by freezing at -70° C. then thawing. The cells wereincubated for one hour at room temperature (R/T) with PBS/3% BSA (washbuffer, bovine serum albumin), then rinsed with a fresh aliquot of washbuffer. Cells were incubated with 50 μl of primary antibodies monoclonalanti-human transglutaminase mouse antibody (IgG) obtained fromBiomedical Industries diluted 1:2,000 in wash buffer for one hour, 37°C. then rinsed two times with wash buffer. Cells were then incubatedwith 50 μl of secondary antibody (Fab fragment, peroxidase conjugatedanti-mouse IgG obtaining from Amersham) diluted 1:4,000 in wash bufferfor one hour at 37° C., then rinsed two times with wash buffer. Cellswere incubated with substrate solution (4 mg o-phenylene diamine and 3,3μl 30% H₂ O₂ in 10 ml 0.1M citrate buffer pH 5.0) for five minutes, R/T,in darkness (under aluminum foil). The reaction was stopped by theaddition of 50 μl 4N H₂ SO₄. The absorbance of samples was read at 492nm in the plate reader. Out of the six replicates, four were treatedwith both antibodies, two were treated only with the secondary antibody(i.e., to determine background binding of enzyme conjugated Ab). TGaselevels were determined by subtracting background from the readings fromeach treatment and determining mean±s.d. for the replicates exposed toboth Ab.

DNA Assay

The level of TGase-1 detected after treatment of the cells could beinfluenced by cell number, i.e., the greater the number of cells thegreater the level of TGase-1 detected. The level of TGase-1 wasnormalized to DNA content of the cells in the same well thus eliminatingvariation due to differences in cell number. DNA quantitation is aparticularly useful indicator of cell number, including keratinocytecell number, because each cell has to all intents and purposes anidentical genome and therefore an identical quantity of DNA. The totalDNA content of a well of cells therefore is directly proportional to thecell number in that well. Quantitation of DNA was used to normalize theTGase data to cell number.

Keratinocytes were plated in 96 well plates at a density of 3,000 cellsper well in 200 μl media. After incubation for four days the media waschanged for media containing test compounds (6 replicates per test). Thecells were cultured for a further 72 hours after which time the mediawas aspirated and the plates stored for at least 1.5 hours at -70° C.Plates were removed from the freezer and thawed for 30 minutes. 100μl/well of Hoechst dye (1 μg/ml final concentration) was added and thiswas incubated for 15 minutes, covered and then read in a fluorimeter(ex. 360 nm and em. 460 nm). The dye solution was removed and the wellswere rinsed with PBS in preparation for the TGase assay.

EXAMPLE 1 Retinoic Acid is More Effective than Retinol at AlteringKeratinocyte Differentiation State

A. The effect on incorporation of ³ H-thymidine μg soluble protein 24hours after the addition of retinoic acid or retinol at variousconcentrations was examined. The results that were obtained aresummarized in Table 1A.

                                      TABLE 1A                                    __________________________________________________________________________    Effect of Retinoic Acid (RA) and                                              Retinol (ROH) on Keratinocyte Thymidine Incorporation                                  mean Thymidine                                                                incorp./μg                                                                 protein ± s.d                                                                        p value vs                                                                         p value vs                                                                          p value vs                                                                          p value vs                                Treatment                                                                              (% control)                                                                             Control                                                                            10.sup.-7 M ROH                                                                     10.sup.-8 M ROH                                                                     10.sup.-9 M ROH                           __________________________________________________________________________    Control  2094 ± 140                                                                       (100%)                                                                            --   0.202 0.501 0.203                                     2.5 × 10.sup.-7 M RA                                                             2475 ± 116                                                                       (118%)                                                                            0.005                                                                              0.032 0.004 0.002                                     2.5 × 10.sup.-7 M ROH                                                            2218 ± 73                                                                        (106%)                                                                            0.202                                                                              --    0.021 0.005                                     2.5 × 10.sup.-8 M RA                                                             2686 ± 72                                                                        (128%)                                                                            0.001                                                                              0.001 0.001 0.001                                     2.5 × 10.sup.-8 M ROH                                                            2034 ± 46                                                                        (97%)                                                                             0.501                                                                              0.021 --    0.121                                     2.5 × 10.sup.-9 M RA                                                             2556 ± 80                                                                        (122%)                                                                            0.001                                                                              0.006 0.001 0.001                                     2.5 × 10.sup.-9 M ROH                                                            1977 ± 19                                                                        (94%)                                                                             0.203                                                                              0.005 0.121 --                                        __________________________________________________________________________     n = 3                                                                    

All concentrations of retinoic acid tested, i.e., 2.5×10⁻⁷ M, 2.5×10⁻⁸and 2.5×10⁻⁹ M, significantly increased keratinocyte proliferation overboth the ethanol control and each of the 2.5×10⁻⁷ M, 2.5×10⁻⁸ M and2.5×10⁻⁹ M retinol treatments and they did so in a dose dependantmanner. This is consistent with retinoic acid having a greaterstimulatory effect on epithelial proliferation than retinol.

B. The effect on Transglutaminase levels normalized to DNA content ofthe cells after addition of retinoic acid and retinol was examined andthe results are shown in Table 1B.

                                      TABLE 1B                                    __________________________________________________________________________             mean TGase/                                                                   DNA × 10.sup.-4 ± s.d                                                           p value vs                                                                         p value vs                                                                         p value vs                                                                         p value vs                                 Treatment                                                                              (% control)                                                                              Control                                                                            10.sup.-7 ROH                                                                      10.sup.-8 ROH                                                                      10.sup.-9 ROH                              __________________________________________________________________________    Control  2.44 ± 0.24                                                                      (100%)                                                                             --   0.001                                                                              0.001                                                                              0.001                                      2.5 × 10.sup.-7 M RA                                                             0.16 ± 0.11                                                                      (7%) 0.001                                                                              0.001                                                                              0.001                                                                              0.001                                      2.5 × 10.sup.-7 M ROH                                                            1.14 ± 0.22                                                                      (47%)                                                                              0.001                                                                              --   0.001                                                                              0.001                                      2.5 × 10.sup.-8 M RA                                                             1.34 ± 0.40                                                                      (55%)                                                                              0.001                                                                              0.001                                                                              0.001                                                                              0.001                                      2.5 × 10.sup.-8 M ROH                                                            1.89 ± 0.30                                                                      (77%)                                                                              0.001                                                                              0.001                                                                              --   0.001                                      2.5 × 10.sup.-9 M RA                                                             1.87 ± 0.49                                                                      (77%)                                                                              0.001                                                                              0.001                                                                              0.784                                                                              0.001                                      2.5 × 10.sup.-9 M ROH                                                            2.70 ± 0.59                                                                      (>100%)                                                                            0.001                                                                              0.001                                                                              0.001                                                                              --                                         __________________________________________________________________________     n = 3                                                                    

All concentrations of retinoic acid tested, i.e., 2.5×10⁻⁷ M, 2.5×10⁻⁸ Mand 2.5×10⁻⁹ M decreased keratinocyte differentiation over both theethanol control and did so to a significantly greater extent than eachof the corresponding 2.5×10⁻⁷ M, 2.5×10⁻⁸ M and 2.5×10⁻⁹ M retinoltreatments. The decrease in transglutaminase level was dose dependentfor both retinoic acid and retinol. This is consistent with retinoicacid having a greater inhibitory effect on epithelial differentiationthan retinol.

EXAMPLE 2 Method of in vitro Microsomal Esterification of Retinol

Microsomes are obtained as described in: J. C. Saari and D. L. Bredberg,"CoA and Non-CoA Dependent Retinol Esterification in Retinal PigmentEpithelium" J. Biol. Chem. 23, 8084-90 (1988).

A solution containing 0.1M sodium phosphate pH 7 buffer, 5 mMdithiothreitol, 2 mg/ml bovine serum albumin, 40 micromolar palmitoylCoA, 40 micromolar dilauroyl phosphatidyl choline, 10 micromolar retinoland a test compound or solvent blank, was incubated for 1 hour at 37° C.with a microsomal fraction isolated from bovine retinal pigmentepithelial cells. After incubation, the reaction was quenched byaddition of an equal volume of ethanol, and the retinyl esters formed(retinyl palmitate from the ARAT catalyzed reaction, and retinyl lauratefrom the LRAT catalyzed reaction) were extracted with hexane. The hexanelayer was removed, evaporated under nitrogen, and the residue analyzedby HPLC on a 3.9×300 mm C18 reversed phase column using a 80% methanolin tetrahydrofuran mobile phase and fluorescence detection (325 nmexcitation, 480 nm emission) to quantitate the retinyl esters. Thequantity of ester formed in the presence of the solvent blank was takenas 100%, and this was used to calculate the percent inhibition of esterformation for the compounds tested. As a control, an aliquot ofmicrosomes was inactivated by boiling for 5 minutes, which resulted inat least 95% inhibition of ester formation.

The results that were obtained are summarized in Table 2.

                  TABLE 2                                                         ______________________________________                                                   CONCENTRATION % INHIB.  % INHIB.                                   COMPOUND   (μM)       ARAT      LRAT                                       ______________________________________                                        Geranyl Geraniol.sup.1                                                                   100           81        77                                         Geranyl Geraniol                                                                         10            38        16                                         Farnesol.sup.2                                                                           100           43        43                                         Farnesol   10            20        10                                         ______________________________________                                         .sup.1 Obtained from TCI America (Portland, Oregon). Also available from      Sigma and CTC Organics (Atlanta, Georgia).                                    .sup.2 Available from Givaudan Co., Bedoukian Co., or Dragoco Co.        

It can be seen from the results in Table 2 that geranyl geraniol is asubstantially more potent esterification inhibitor, than farnesol, thestructure for which is as follows: ##STR3##

EXAMPLE 3

³ H-Thymidine incorporation was measured according to the proceduredescribed in Materials and Methods section above. The results that wereobtained are summarized below:

    ______________________________________                                                    DPM/Microgram Protein                                             Treatment     mean      (s.d.)     % Control                                  ______________________________________                                        Experiment #1                                                                 Control       1930      (278)      100                                        250 nM retinol                                                                              2082      (146)      108                                        250 nM retinoic acid                                                                        3013      (226)      156                                        250 nM retinol + 10 nM                                                                      2970      (308)      154                                        geranyl geraniol                                                              Experiment #2                                                                 Control       915       (322)      100                                        250 nM retinol                                                                              974       (148)      107                                        250 nM retinoic acid                                                                        1494       (45)      163                                        250 nM retinol + 10 nM                                                                      1450      (318)      159                                        geranyl geraniol                                                              ______________________________________                                    

It can be seen from the results above that geranyl geraniol is able tosignificantly increase the proliferation enhancing effect of retinol toa level similar to that which can be achieved with a comparable amountof retinoic acid.

EXAMPLE 4

This example illustrates a high internal phase water-in-oil emulsionincorporating the inventive composition.

    ______________________________________                                                          % w/w                                                       ______________________________________                                        Retinol             0.5                                                       Fully hydrogenated coconut oil                                                                    3.9                                                       Geranyl geraniol    2                                                         Brij 92*            5                                                         Bentone 38          0.5                                                       MgSO.sub.4 7H.sub.2 O                                                                             0.3                                                       Butylated hydroxy toluene                                                                         0.01                                                      Perfume             qs                                                        Water               to 100                                                    ______________________________________                                         *Brij 92 is polyoxyethylene (2) oleyl ether                              

EXAMPLE 5

This example illustrates an oil-in-water cream incorporating theinventive composition.

    ______________________________________                                                         % w/w                                                        ______________________________________                                        Retinol            0.15                                                       Mineral oil        4                                                          Geranyl geraniol   1                                                          Brij 56*           4                                                          Alfol 16RD*        4                                                          Triethanolamine    0.75                                                       Butane-1,3-diol    3                                                          Xanthan gum        0.3                                                        Perfume            qs                                                         Butylated hydroxy toluene                                                                        0.01                                                       Water              to 100                                                     ______________________________________                                         *Brij 56 is cetyl alcohol POE (10)                                            Alfol 16RD is cetyl alcohol                                              

EXAMPLE 6

This example illustrates an alcoholic lotion incorporating thecomposition according to the invention.

    ______________________________________                                                         % w/w                                                        ______________________________________                                        Retinyl palmitate  0.15                                                       Geranyl geraniol   0.1                                                        Ethanol            40                                                         Perfume            qs                                                         Butylated hydroxy toluene                                                                        0.01                                                       Water              to 100                                                     ______________________________________                                    

EXAMPLE 7 This example illustrates another alcoholic lotion containingthe inventive composition.

    ______________________________________                                                      % w/w                                                           ______________________________________                                        Retinol         0.15                                                          Geranyl geraniol                                                                              2                                                             Ethanol         40                                                            Antioxidant     0.1                                                           Perfume         qs                                                            Water           to 100                                                        ______________________________________                                    

EXAMPLE 8

This example illustrates a suncare cream incorporating the compositionof the invention:

    ______________________________________                                                            % w/w                                                     ______________________________________                                        Retinol               0.01                                                    Geranyl geraniol      1                                                       Silicone oil 200 cts  7.5                                                     Glycerylmonostearate  3                                                       Cetosteryl alcohol    1.6                                                     Polyoxyethylene-(20)-cetyl alcohol                                                                  1.4                                                     Xanthan gum           0.5                                                     Parsol 1789           1.5                                                     Octyl methoxycinnate (PARSOL MCX)                                                                   7                                                       Perfume               qs                                                      Color                 qs                                                      Water                 to 100                                                  ______________________________________                                    

EXAMPLE 9

This example illustrates a non-aqueous skin care compositionincorporating inventive combination.

    ______________________________________                                                         % w/w                                                        ______________________________________                                        Retinyl palmitate  0.15                                                       Geranyl geraniol   1                                                          Silicone gum SE-30.sup.1                                                                         10                                                         Silicone fluid 345.sup.2                                                                         20                                                         Silicone fluid 344.sup.3                                                                         55.79                                                      Squalene           10                                                         Linoleic acid      0.01                                                       Cholesterol        0.03                                                       2-hydroxy-n-octanoic acid                                                                        0.7                                                        Vitamin E linoleate                                                                              0.5                                                        Herbal oil         0.5                                                        Ethanol            2                                                          ______________________________________                                         .sup.1 A dimethyl silicone polymer having a molecular weight of at least      50,000 and a viscosity of at least 10,000 centistokes at 25° C.,       available from GEC                                                            .sup.2 Dimethyl siloxane cyclic pentamer, available from Dow Corning Corp     .sup.3 Dimethyl siloxane tetramer, available from Dow Corning Corp.      

It should be understood that the specific forms of the invention hereinillustrated and described are intended to be representative only.Changes, including but not limited to those suggested in thisspecification, may be made in the illustrated embodiments withoutdeparting from the clear teachings of the disclosure. Accordingly,reference should be made to the following appended claims in determiningthe full scope of the invention.

What is claimed is:
 1. A skin conditioning composition comprising(a) from about 0.001% to about 10% of retinal; (b) from about 0.0001% to about 50% of geranyl geraniol; and (c) a cosmetically acceptable vehicle.
 2. A method of treating a skin condition selected from the group consisting of dry skin, photodamaged skin, wrinkles, age spots, acne, skin lightening, psoriasis and atopic dermatosis, the method comprising applying to the skin the composition of claim
 1. 